Ferroelectric Hafnium Oxide Material Enhanced Reliability

该项目的主要目标是了解电介质与电容器结构中HfO2或zro2基铁电层之间的相互作用。在这种双层结构中，铁电偶极子与电荷（如电子、空穴、带电氧空位）之间发生强烈的相互作用。从铁电电容器到铁电场效应晶体管和铁电隧道结，再到负电容场效应管和红外传感器，各种半导体器件中存在着不同厚度比的介电层和铁电层，不同器件的效应可能不同，但基本特性是相似的。到目前为止，对缺陷和电荷影响的详细了解有限，迫切需要进一步的研究，以使HfO2基铁电材料的广泛应用成为可能。在HfO2-和zro2基铁电层中掺杂不同原子价的原子，以了解掺杂原子价对铁电电容器可靠性（记忆窗口、泄漏、唤醒行为、保持、疲劳和耐久性）的影响。此外，还将研究铁电/介电层厚度比以及电极材料对电容器膜堆的影响，以减少捕获行为，获得更好的性能。为了获得这些结果，将通过不同的表征技术来研究活性介质的电子和原子结构，并通过从头算模拟的实验发光和电荷输运实验来补充和加强。获得的结果允许获得铁电性能退化行为的详细微观模型，以便为铁电器件开发实用的建议。该项目的总体目标是在可靠性、性能、环境兼容性、CMOS兼容性和基础材料的可用性方面优化这种新型无铅铁电材料。

The main objective of the project is to understand the interplay between a dielectric and a HfO2- or ZrO2-based ferroelectric layer within a capacitor structure. Within this bi-layer structure stack a strong interaction between the ferroelectric dipoles and charges (e.g. electrons, holes, charged oxygen vacancies) occur. Since different thickness ratio of dielectric and ferroelectric layer are present in a wide range of semiconductor devices from ferroelectric capacitor via ferroelectric field effect transistors and ferroelectric tunnel junctions to negative capacitance FETs and infrared sensors, effects might change from one device to another, but basic characteristics remain similar. So far, a detailed understanding of the effects of defects and charges is limited, and further studies are urgently needed to make the introduction of HfO2 based ferroelectric materials in a wide range of applications possible. HfO2- and ZrO2-based ferroelectric layers are doped by atoms with different valence to understand the impact of dopant valence on the ferroelectric capacitor reliability (memory window, leakage, wake-up behavior, retention, fatigue, and endurance). Furthermore, the impact of the thickness ratio of ferroelectric/dielectric layers as well as electrode materials will be studied on the capacitor film stacks to reduce trapping behavior and get better performance. To achieve these results, the electronic and atomic structure of active mediums will be studied by different characterization techniques which will be supplemented and strengthened by experimental luminescence and charge transport experiments with ab initio simulations. Obtained results allow to obtain a detailed microscopic model for the degradation behavior of ferroelectric properties in order to develop practical recommendations for ferroelectric devices. The overall goal of the project is an optimization of this new lead-free ferroelectric material with respect to reliability, performance, environmental compatibility, CMOS compatibility, availability of the basic material.